Digital dithering for reduction of quantization errors and side-lobe levels in phased array antennas

ABSTRACT

Systems and methods disclosed herein provide techniques for reducing quantization errors and side lobe levels in phased array antennas. The states of a quantized phase shifter of a phased array antenna may be dithered to achieve a time-averaged value that reduces quantization errors. By rapidly switching between the different states of the quantized phase shifter, a time-average value close to a desired phase state may be achieved with a low resolution phase shifter.

TECHNICAL FIELD

The present disclosure relates generally to phased array antennas. Moreparticularly, some embodiments of the present disclosure are directedtoward systems and methods for using digital dithering for reduction ofquantization errors and side-lobe levels in phased array antennas.

BACKGROUND

Phased array antennas include multiple transmitting and/or receivingantenna elements that can be used together to form a directionalradiation pattern. The relative phases or the respective signals feedingthe antennas are controlled to create an effective radiation patternthat is strongest in a desired direction and suppressed in undesireddirections. In this manner the antenna beam may be rapidly steeredwithout any mechanical steering of the antenna (e.g., using a gimbal).

When quantized phase shifters are used to control the phases of thesignals feeding the antenna elements, quantization errors result fromthe finite number of digitalization bits available to represent a signalphase. For example, in the case of a 2-bit phase shifter with fourstates, 0°, 90°, 180°, and 270°, the step size is 90° and the maximumquantization error is ±45°. When a radiating element requires a phase of46°, the nearest state of this phase shifter is 90°, for which the error(between desired and actual) is 44°.

Quantization errors degrade antenna performance by increasing side lobelevels (SLL), i.e. the power density of side lobes that representunwanted radiation in unwanted directions. Using a phase shifter with agreater number of quantization bits may improve antenna efficiency andlower SLLs, but it comes at the cost of a more expensive and complexphase shifter and control circuit.

SUMMARY

Systems and methods disclosed herein provide techniques for reducingquantization errors and side lobe levels in phased array antennas.

In one embodiment, a method includes: receiving an input signal at aquantized phase shifter of a phased array antenna; dithering the statesof the quantized phase shifter to obtain a time averaged, phase shiftedsignal; and outputting the time averaged, phase shifted signal to anantenna element circuit of the phased array antenna. In someimplementations the quantized phase shifter may be a 1-bit or 2-bitphase shifter. In one implementation, dithering the states of thequantized phase shifter comprises switching between the states of thequantized phase shifter at a rate greater than the highest symbol rateof an adjacent satellite. In a particular implementation, the states ofthe quantized phase shifter are switched at a rate at least four timesgreater than the highest symbol rate of an adjacent satellite.

In implementations, the states of the quantized phase shifter aredithered using linear interpolation or accumulator interpolation. In aparticular implementation, dithering the states of the quantized phaseshifter comprises: obtaining an error signal by comparing an outputphase to a required phase; providing the error signal as an input to anintegrator to obtain an integrated signal; unwrapping the output phaseof the integrated signal to obtain an unwrapped signal; and quantizingthe unwrapped signal.

The quantized phase shifter may provides a constant phase shift of aninput signal over a frequency or the quantized phase shifter may providea true time delay of an input signal.

In one embodiment, a phase array antenna includes: a plurality ofquantized phase shifters; a controller configured to dither the statesof each of the plurality of quantized phase shifters; and a plurality ofantenna elements, where each of the plurality of antenna elements isconfigured to receive a time-averaged, phase shifted signal from arespective one of the plurality of quantized phase shifters. The phasedarray antenna may be a phased array antenna of a very small apertureterminal (VSAT). The phased array antenna may also be a phased arrayantenna of a satellite.

The techniques disclosed herein may be implemented in a phased arrayantenna receiver. In one embodiment, a method includes: receiving an RFcommunication signal at each of a plurality of antenna elements of aphased array antenna; outputting a signal from an antenna element to aquantized phase shifter; and dithering the states of the quantized phaseshifter to obtain a time averaged, phase shifted signal. In thisembodiment dithering the states of the quantized phase shifter maycomprise switching between the states of the quantized phase shifter,and the states of the quantized phase shifter may be dithered usinglinear interpolation or accumulator interpolation. In an implementation,the method further comprises: amplifying the RF communication signalreceived at each of the plurality of antenna elements using a low noiseamplifier.

Other features and aspects of the disclosure will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, which illustrate, by way of example, the featuresin accordance with various embodiments. The summary is not intended tolimit the scope of the invention, which is defined solely by the claimsattached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The technology disclosed herein, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures. The drawings are provided for purposes of illustration only andmerely depict typical or example embodiments of the disclosedtechnology. These drawings are provided to facilitate the reader'sunderstanding of the disclosed technology and shall not be consideredlimiting of the breadth, scope, or applicability thereof. It should benoted that for clarity and ease of illustration these drawings are notnecessarily made to scale.

FIG. 1 is a block diagram illustrating an example bi-directional phasedarray antenna in which embodiments may be implemented.

FIG. 2 illustrates one particular implementation of a phased arrayantenna whereby elements are arranged in a circular array and are spacedapart in half wavelengths.

FIG. 3 is a block diagram illustrating an example implementation inwhich controller dithers quantized phase shifters of a phased arrayantenna.

FIG. 4 is a flow diagram illustrating an example method of dithering thestates of quantized phase shifters in a phased array antenna to reducequantization errors and side lobe levels in the phased array antenna.

FIG. 5 is a diagram illustrating an example digital dithering algorithmthat may be applied to a 2-bit phase shifter in accordance withembodiments.

FIG. 6A depicts experimental results illustrating the time-averageddirectivity pattern of a beam transmitted at 30 GHz using a phased arrayantenna that dithers 2-bit phase shifters.

FIGS. 6B depicts experimental results illustrating the time-averageddirectivity pattern of a beam transmitted at 30 GHz using a phased arrayantenna that does not dither.

FIG. 7 illustrates an example computing module that may be used inimplementing features of various embodiments.

FIG. 8 illustrates an example chip set that can be utilized inimplementing architectures and methods for digital dithering forreduction of quantization errors and side-lobe levels in phased arrayantennas in accordance with various embodiments.

The figures are not intended to be exhaustive or to limit the inventionto the precise form disclosed. It should be understood that theinvention can be practiced with modification and alteration, and thatthe disclosed technology be limited only by the claims and theequivalents thereof.

DETAILED DESCRIPTION

As alluded to above, conventional phased array antennas that utilizequantized phase shifters rely on high bit phase shifters to minimizequantization errors. However, this increases the cost of the antenna ina number of areas: (1) the phase shifter devices themselves (costsapproximately proportional to the number of bits), (2) the controlcircuitry, as its complexity increases with the number of phase shiftingbits; (3) the transmission lines, typically waveguides or PrintedCircuit Boards (PCB), as they become more complex with the number ofphase shifting bits.

Embodiments of the systems and methods disclosed herein providetechniques for addressing the aforementioned problems by dithering thestate of the quantized phase shifter to achieve a time-average valuethat significantly reduces quantization errors of the quantized phaseshifter. By rapidly switching between the different states of thequantized phase shifter, a time-average value close to a desired phasestate may be achieved even with a low resolution (e.g., 1-bit or 2-bit)phase shifter. This method may provide a number of advantages overconventional approaches of using phase shifters with higher bit-counts.First, this method reduces the quantization error and reduces antennaSLL, all at no additional hardware cost. Second, this method negates therequirement for calibration that is typical in phase shifter hardwareimplementations of any number of bits, but particularly high number ofbits. This results in significant cost savings as calibration is quitetime consuming, requires precision measurement instruments, andtypically represents a significant percentage of system costs.

FIG. 1 is a block diagram illustrating an example bi-directional phasedarray antenna 100, including antenna elements 150, in which embodimentsmay be implemented. Although a bi-directional phased array antenna 100is shown in this example, the methods disclosed herein may implementedin unidirectional transmit phased array antennas. Phased array antennamay be implemented as a dynamic phased array antenna (i.e., each antennaelement or group of elements may have an adjustable phase shifter), anactive phased array antenna (i.e., each antenna element or groupelements may have transmit amplification circuitry), a passive phasedarray antenna, or some variant thereof.

Phased array antenna 100 may be implemented in a variety of devices. Forexample, in one implementation phased array antenna 100 may beimplemented in a fixed terminal (e.g., a VSAT terminal) communicatingwith a satellite. In such implementations, the technology disclosedherein may offer an affordable way of steering the antenna beam,automatically pointing the beam to the satellite, and periodicallyrepointing the antenna beam to compensate for minor antenna movementsdue to ground settlement, ground freezing/thawing cycles, etc. In otherimplementations, phased array antenna 100 may be implemented in movingsatellites (e.g., a low earth orbit satellite, a medium earth orbitsatellite, etc.) and/or moving terminals that are on moving platforms(e.g., on a terrestrial vehicle or aircraft). In such implementations,the technology disclosed herein may provide an affordable way of fastbeam tracking that constantly points the antenna beam towards thesatellite.

As illustrated by FIG. 1, example phased array antenna 100 includes apower divider 120, transmit amplifiers 130, antenna elements 150, one ormore low noise amplifiers 140, power combiner 160, dithered andquantized phase shifter module 200, and controller 300. It should benoted that one of ordinary skill in the art will understand how othertransmit or receive configurations can be implemented in phased arrayantenna 100, and that certain components of phased array antenna 100 maybe implemented in either digital form (e.g., as software running on aDSP or other processing device, with the addition of a DAC) or as analogcomponents. Additionally, although the components of phased arrayantenna 100 are shown in a particular order in this example, one ofordinary skill in the art reading this description will understand thatthe order of components can be varied and some components may beexcluded. For simplicity, a discussion of the receive operation ofphased array antenna 100, and receive components such as LNAs 140, powercombiner 160, and receiver 170 will be omitted. However, one havingskill in the art will appreciate how such components may implement thereverse operation of the transmit components described herein.

During transmit operation, illustrated by FIG. 1, phased array antenna100 may steer an antenna beam 400 in a direction by varying the phasesof radiating antenna elements 150 so as to produce an effectiveradiation pattern (as determined by constructive and destructiveinterference of the signals emitted by each antenna element 150) in adesired direction (azimuthal and/or elevation). For example, the phaseof every radiating antenna element 150 may be varied such that there isprogressive phase along the rows and/or columns of the radiatingelements. As further described below, this may be implemented by using aphase shifter (for every radiating element or group of elements) thatcan vary the phase of the RF energy radiated by the respective element.As illustrated in this example, a beam 400 is steered at an angle θrelative to elements 150 and includes a main lobe 410 and side lobes420A-420B.

With specific reference to the elements of phased array antenna 100during a transmit operation, phased array antenna 100 receives an RFsignal from an RF source 110. For example, RF source 110 may take a bitsource as an input and perform functions such as signal encoding,interleaving, modulation, and filtering. Signals coming from RF source110 may be based, for example, on the DVB-S2 standard (ETSI EN 302 307)using signal constellations up to and including at least 32-APSK, or onthe Internet Protocol over Satellite (IPoS) standard (ETSI TS 102 354),or on other standard or proprietary specifications incorporatingadaptive coding and modulation. Other suitable signal types may also beused, including, for example higher data rate variations of DVB-S2, orDVB-S2 extensions or adaptations sometimes designated as DVB-S2X.

Additionally, RF source 110 may modulate an information signal onto asuitable carrier (e.g., an RF carrier signal) at a desired frequency.For example, phased array antenna 100 may operate in the Ka-band,Ku-band, C-band or other suitable band. However, it should be noted thatthe up conversion or modulation of the signal onto a suitable carriermay be performed before or after the phase delay.

Power divider 120 may couple a defined amount of power of a signalprovided by RF source 110 to a plurality of signal paths, each of thedivided signals being fed along a path to an antenna element 150. Forinstance, in implementations where each antenna element 150 includes arespective phase shifter, power divider 120 may feed a respectiveinstance of a signal to the phase shifter, which is phase shifted at aquantized phase shifter of module 200, amplified by amplifier 130 andtransmitted by an antenna element 150.

Depending on the implementation, antenna elements 150 may be arranged ina variety of configurations. For example, antenna elements 150 may belinearly arranged in a linear array, in a rectangular array, a circulararray, or some other suitable arrangement. Within the arrangement,antenna elements 150 may be spaced apart depending on the wavelength ofthe transmitted waveform. For example, elements 150 may be spaced apartin half wavelengths or quarter wavelengths. The number of antennaelements 150 may depend on the gain requirements of phased array antenna100 and the type of radiator used for each antenna element. For example,a 20 dB gain antenna may require about 100 elements or more, a 30 dBgain antenna may require about 1000 elements or more, and a 40 dBantenna may require about 10,000 elements or more, and so forth. FIG. 2illustrates one particular implementation of a phased array antennawhereby elements 150 are arranged in a circular array and are spacedapart in half wavelengths.

Dithered and quantized phase shifter module 200, may include a quantizedphase shifter for each element 150 or group of elements 150 that changesthe transmission phase angle or true time delay of a signal transmittedby a respective element 150. Each quantized phase shifter is digitallycontrolled using one or more bits (e.g., 1 bit, 2 bits, 3 bits, etc.),which provide a discrete set of states that are controlled using acontroller 300. For example, as discussed above, a two bit phase shiftermay have four states: 0°, 90°, 180°, and 270°. As another example, athree bit phase shifter may include eight states: 0°, 45°, 90°, 135°,180°, 225°, 270°, and 315°. In some implementations, the quantized phaseshifters may provide a true time delay as opposed to a constant phaseshift over a frequency. For ease of discussion, as used herein, the term“quantized phase shifter” refers to either a phase shifter that providesa constant phase shift over a frequency or a true time delay. Similarly,the term “n-bit phase shifter” may refer to either variety of phaseshifter that can be controlled using n digital bits.

During operation, further described below, controller 300 may cause eachquantized phase shifter to rapidly switch between each of its states(e.g., using pulse width modulation), thereby effectively dithering theoutput of the phase shifter and reducing quantization error. Forexample, consider the case of a 2-bit phase shifter (including states 0°and 90°) and desired phase angle of 22.5 for an antenna element 150. Byrapidly switching between the 0° and 90° states with a 75% duty cycle inthe 0° state and a 25% duty cycle in the 90° state (e.g., three 0°states for every one 90° state), the time-averaged value of the state ofthe quantized phase shifter is 22.5°, thereby effectively reducing thequantization error to 0° and providing the same resolution as a 4-bitphase shifter. This in turn may reduce side lobe degradation of thedirectional beam transmitted by the phased array antenna. As anotherexample, consider the case of a 2-bit phase shifter (including states of1 μs and 2 μs) and desired true time delay of 1.5 μs for an antennaelement 150. By rapidly switching between the 1 μs and 2 μs states atthe same duty cycle, the time-averaged value of the state of thequantized phase shifter is 1.5 μs.

FIG. 3 is a block diagram illustrating an example implementation inwhich controller 300 dithers quantized phase shifters 250-1 to 250-N ofa phased array antenna. In this example, controller 300 may cause phaseshifters 250-1 to 250-N to rapidly cycle between their states based on adesired phase shift. FIG. 3 will be described in conjunction with FIG.4, which is a flow diagram illustrating an example method 400 ofdithering the states of quantized phase shifters in a phased arrayantenna to reduce quantization errors and side lobe levels in the phasedarray antenna.

At operation 410, input signals are received at quantized phase shifters250-1 to 250-N. For example, individual instances of the same RF signalmay be delivered to a respective quantized phase shifter 250-1configured to generate a respective phase delay.

At operation 420, the states of each quantized phase shifter 250-1 to250-N is dithered using controller 300 to generate a time-averaged phaseshifted signal. In various implementations, the state of each quantizedphase shifter may be dithered by switching or cycling between the statesof the quantized phase shifter at a frequency greater than the highestsymbol rate of an adjacent satellite. In particular implementations,switching may occur at a frequency of at least four times the highestsymbol rate of the adjacent satellite. For example, if an adjacent Kusatellite operates using 40 MHz transponders, switching may occur at arate of 160 MHz or greater. At operation 430, the phase shifted signalsare output to respective antenna element circuits.

Digital dithering of a phase shifter's state may be implemented using avariety of algorithms that cycle through the phase shifter states givena desired phase shift. For example, linear interpolation, the use ofaccumulator interpolation, or other types of algorithms may beimplemented. During each cycle, the quantized phase may be used tocreate a power radiation pattern using a signal with a bandwidth that ismuch higher than that of the neighboring satellite. A group of patterns,which are produced from individual cycles, may then be averaged toproduce a compliant radiation pattern. In implementations, the number ofcycles may be chosen such that the side lobes produced by the phasedarray antenna are sufficiently suppressed to a given level (e.g., indBi).

In implementations, controller 300 may be embedded in a chip that has aplurality of switches for controlling the states of quantized phaseshifters 250-1 to 250-N. For example, controller 300 may be implementedas a complimentary metal-oxide-semiconductor (CMOS) controller on a chipcomprising silicon-germanium switches. In implementations, a chipincluding the quantized phase shifters, may be embedded with analgorithm that may be used to dither the states of the quantized phaseshifters.

FIG. 5 is a block diagram illustrating an example digital ditheringalgorithm that may be applied to a 2-bit phase shifter in accordancewith embodiments. As illustrated, the algorithm includes a subtractor510, an integrator 520 including an adder 525 and digital sample delaymodule 527, a phase unwrapping module 530, and a quantizer 540 (2-bitsin this example).

As illustrated by FIG. 5, the output phase Q_(out) that is a result ofquantization with a limited number of bits (2 bits in this example) iscompared to a required phase Q_(req) that is exact. An error is producedas a result of this comparison. This error is then provided as an inputto integrator 520. The output phase is unwrapped using unwrapping module530 to fall within the range of the quantized phase, that is [0°, 360°).The output is then quantized by quantizer 540 based on the number ofbits specified by the quantizer.

The loop cycle shown in FIG. 5 may be performed multiple times (e.g.,two times, four times, ten times, etc.) and the radiated power of allthe cycles is averaged to produce a dithered power radiation pattern. Inimplementations, the signals transmitted over individual cycles aretransmitted over a bandwidth that is much wider (e.g., at least fourtimes) than the measurable bandwidth of the neighboring satellite. Theresultant averaged, or dithered, power radiation pattern may becompliant with FCC 25.209.

FIG. 6A shows experimental results illustrating the time-averageddirectivity pattern (i.e., antenna gain in dBi as a function of scanangle) of a beam transmitted at 30 GHz using a phased array antenna thatdithers 2-bit phase shifters. In the examples of FIG. 6A, the 2-bitphase shifters were dithered using the digital dithering algorithmillustrated in FIG. 5. FIG. 6B illustrates the directivity pattern whenthere is no dithering (one clock cycle). FIG. 6A illustrates thedirectivity pattern when there is dithering for ten clock cycles. Theaveraged array directivity pattern 610 after ten cycles hassubstantially reduced side lobes and is on par with earth stationantenna performance standards as prescribed by FCC Rule 25.209. The maxaverage directivity power in the main lobe (scan angle of 0°) is over 44dBi.

FIG. 7 illustrates a computer system 1000 upon which example embodimentsaccording to the present disclosure can be implemented. Computer system1000 can include a bus 1002 or other communication mechanism forcommunicating information, and a processor 1004 coupled to bus 1002 forprocessing information. Computer system 1000 may also include mainmemory 1006, such as a random access memory (RAM) or other dynamicstorage device, coupled to bus 1002 for storing information andinstructions to be executed by processor 1004. Main memory 1006 can alsobe used for storing temporary variables or other intermediateinformation during execution of instructions to be executed by processor1004. Computer system 1000 may further include a read only memory (ROM)1008 or other static storage device coupled to bus 1002 for storingstatic information and instructions for processor 1004. A storage device1010, such as a magnetic disk or optical disk, may additionally becoupled to bus 1002 for storing information and instructions.

Computer system 1000 can be coupled via bus 1002 to a display 1012, suchas a cathode ray tube (CRT), liquid crystal display (LCD), active matrixdisplay, light emitting diode (LED)/organic LED (OLED) display, digitallight processing (DLP) display, or plasma display, for displayinginformation to a computer user. An input device 1014, such as a keyboardincluding alphanumeric and other keys, may be coupled to bus 1002 forcommunicating information and command selections to processor 1004.Another type of user input device is cursor control 1016, such as amouse, a trackball, or cursor direction keys for communicating directioninformation and command selections to processor 1004 and for controllingcursor movement on display 1012.

According to one embodiment of the disclosure, dithering of thequantized phase shifter, in accordance with example embodiments, isprovided by computer system 1000 in response to processor 1004 executingan arrangement of instructions contained in main memory 1006. Suchinstructions can be read into main memory 1006 from anothercomputer-readable medium, such as storage device 1010. Execution of thearrangement of instructions contained in main memory 1006 causesprocessor 1004 to perform one or more processes described herein. One ormore processors in a multi-processing arrangement may also be employedto execute the instructions contained in main memory 1006. Inalternative embodiments, hard-wired circuitry is used in place of or incombination with software instructions to implement various embodiments.Thus, embodiments described in the present disclosure are not limited toany specific combination of hardware circuitry and software.

Computer system 1000 may also include a communication interface 1018coupled to bus 1002. Communication interface 1018 can provide a two-waydata communication coupling to a network link 1020 connected to a localnetwork 1022. By way of example, communication interface 1018 may be adigital subscriber line (DSL) card or modem, an integrated servicesdigital network (ISDN) card, a cable modem, or a telephone modem toprovide a data communication connection to a corresponding type oftelephone line. As another example, communication interface 1018 may bea local area network (LAN) card (e.g. for Ethernet™ or an AsynchronousTransfer Model (ATM) network) to provide a data communication connectionto a compatible LAN. Wireless links can also be implemented. In any suchimplementation, communication interface 1018 sends and receiveselectrical, electromagnetic, or optical signals that carry digital datastreams representing various types of information. Further,communication interface 1018 may include peripheral interface devices,such as a Universal Serial Bus (USB) interface, a PCMCIA (PersonalComputer Memory Card International Association) interface, etc.

Network link 1020 typically provides data communication through one ormore networks to other data devices. By way of example, network link1020 can provide a connection through local network 1022 to a hostcomputer 1024, which has connectivity to a network 1026 (e.g. a widearea network (WAN) or the global packet data communication network nowcommonly referred to as the “Internet”) or to data equipment operated byservice provider. Local network 1022 and network 1026 may both useelectrical, electromagnetic, or optical signals to convey informationand instructions. The signals through the various networks and thesignals on network link 1020 and through communication interface 1018,which communicate digital data with computer system 1000, are exampleforms of carrier waves bearing the information and instructions.

Computer system 1000 may send messages and receive data, includingprogram code, through the network(s), network link 1020, andcommunication interface 1018. In the Internet example, a server (notshown) might transmit requested code belonging to an application programfor implementing an embodiment of the present disclosure through network1026, local network 1022 and communication interface 1018. Processor1004 executes the transmitted code while being received and/or store thecode in storage device 1010, or other non-volatile storage for laterexecution. In this manner, computer system 1000 obtains application codein the form of a carrier wave.

The term “computer-readable medium” as used herein refers to any mediumthat participates in providing instructions to processor 1004 forexecution. Such a medium may take many forms, including but not limitedto non-volatile media, volatile media, and transmission media.Non-volatile media include, for example, optical or magnetic disks, suchas storage device 1010. Volatile media may include dynamic memory, suchas main memory 1006. Transmission media may include coaxial cables,copper wire and fiber optics, including the wires that comprise bus1002. Transmission media can also take the form of acoustic, optical, orelectromagnetic waves, such as those generated during radio frequency(RF) and infrared (IR) data communications. Common forms ofcomputer-readable media include, for example, a floppy disk, a flexibledisk, hard disk, magnetic tape, any other magnetic medium, a CD ROM,CDRW, DVD, any other optical medium, punch cards, paper tape, opticalmark sheets, any other physical medium with patterns of holes or otheroptically recognizable indicia, a RAM, a PROM, and EPROM, a FLASH EPROM,any other memory chip or cartridge, a carrier wave, or any other mediumfrom which a computer can read.

Various forms of computer-readable media may be involved in providinginstructions to a processor for execution. By way of example, theinstructions for carrying out at least part of the present disclosuremay initially be borne on a magnetic disk of a remote computer. In sucha scenario, the remote computer loads the instructions into main memoryand sends the instructions over a telephone line using a modem. A modemof a local computer system receives the data on the telephone line anduses an infrared transmitter to convert the data to an infrared signaland transmit the infrared signal to a portable computing device, such asa personal digital assistance (PDA) and a laptop. An infrared detectoron the portable computing device receives the information andinstructions borne by the infrared signal and places the data on a bus.The bus conveys the data to main memory, from which a processorretrieves and executes the instructions. The instructions received bymain memory may optionally be stored on storage device either before orafter execution by processor.

FIG. 8 illustrates a chip set 1100 in which embodiments of thedisclosure may be implemented. Chip set 1100 can include, for instance,processor and memory components described with respect to FIG. 8incorporated in one or more physical packages. By way of example, aphysical package includes an arrangement of one or more materials,components, and/or wires on a structural assembly (e.g., a baseboard) toprovide one or more characteristics such as physical strength,conservation of size, and/or limitation of electrical interaction.

In one embodiment, chip set 1100 includes a communication mechanism suchas a bus 1002 for passing information among the components of the chipset 1100. A processor 1104 has connectivity to bus 1102 to executeinstructions and process information stored in a memory 1106. Processor1104 includes one or more processing cores with each core configured toperform independently. A multi-core processor enables multiprocessingwithin a single physical package. Examples of a multi-core processorinclude two, four, eight, or greater numbers of processing cores.Alternatively or in addition, processor 1104 includes one or moremicroprocessors configured in tandem via bus 1102 to enable independentexecution of instructions, pipelining, and multithreading. Processor1004 may also be accompanied with one or more specialized components toperform certain processing functions and tasks such as one or moredigital signal processors (DSP) 1108, and/or one or moreapplication-specific integrated circuits (ASIC) 1110. DSP 1108 cantypically be configured to process real-world signals (e.g., sound) inreal time independently of processor 1104. Similarly, ASIC 1110 can beconfigured to performed specialized functions not easily performed by ageneral purposed processor. Other specialized components to aid inperforming the inventive functions described herein include one or morefield programmable gate arrays (FPGA) (not shown), one or morecontrollers (not shown), or one or more other special-purpose computerchips.

Processor 1104 and accompanying components have connectivity to thememory 1106 via bus 1102. Memory 1106 includes both dynamic memory(e.g., RAM) and static memory (e.g., ROM) for storing executableinstructions that, when executed by processor 1104, DSP 1108, and/orASIC 1110, perform the process of example embodiments as describedherein. Memory 1106 also stores the data associated with or generated bythe execution of the process.

As used herein, the term module might describe a given unit offunctionality that can be performed in accordance with one or moreembodiments of the present application. As used herein, a module mightbe implemented utilizing any form of hardware, software, or acombination thereof. For example, one or more processors, controllers,ASICs, PLAs, PALs, CPLDs, FPGAs, logical components, software routinesor other mechanisms might be implemented to make up a module. Inimplementation, the various modules described herein might beimplemented as discrete modules or the functions and features describedcan be shared in part or in total among one or more modules. In otherwords, as would be apparent to one of ordinary skill in the art afterreading this description, the various features and functionalitydescribed herein may be implemented in any given application and can beimplemented in one or more separate or shared modules in variouscombinations and permutations. Even though various features or elementsof functionality may be individually described or claimed as separatemodules, one of ordinary skill in the art will understand that thesefeatures and functionality can be shared among one or more commonsoftware and hardware elements, and such description shall not requireor imply that separate hardware or software components are used toimplement such features or functionality.

Where components or modules of the application are implemented in wholeor in part using software, in one embodiment, these software elementscan be implemented to operate with a computing or processing modulecapable of carrying out the functionality described with respectthereto. One such example computing module is shown in FIG. 7. Variousembodiments are described in terms of this example-computing module1000. After reading this description, it will become apparent to aperson skilled in the relevant art how to implement the applicationusing other computing modules or architectures.

Although described above in terms of various exemplary embodiments andimplementations, it should be understood that the various features,aspects and functionality described in one or more of the individualembodiments are not limited in their applicability to the particularembodiment with which they are described, but instead can be applied,alone or in various combinations, to one or more of the otherembodiments of the present application, whether or not such embodimentsare described and whether or not such features are presented as being apart of a described embodiment. Thus, the breadth and scope of thepresent application should not be limited by any of the above-describedexemplary embodiments.

Terms and phrases used in the present application, and variationsthereof, unless otherwise expressly stated, should be construed as openended as opposed to limiting. As examples of the foregoing: the term“including” should be read as meaning “including, without limitation” orthe like; the term “example” is used to provide exemplary instances ofthe item in discussion, not an exhaustive or limiting list thereof; theterms “a” or “an” should be read as meaning “at least one,” “one ormore” or the like; and adjectives such as “conventional,” “traditional,”“normal,” “standard,” “known” and terms of similar meaning should not beconstrued as limiting the item described to a given time period or to anitem available as of a given time, but instead should be read toencompass conventional, traditional, normal, or standard technologiesthat may be available or known now or at any time in the future.Likewise, where this document refers to technologies that would beapparent or known to one of ordinary skill in the art, such technologiesencompass those apparent or known to the skilled artisan now or at anytime in the future.

The use of the term “module” does not imply that the components orfunctionality described or claimed as part of the module are allconfigured in a common package. Indeed, any or all of the variouscomponents of a module, whether control logic or other components, canbe combined in a single package or separately maintained and can furtherbe distributed in multiple groupings or packages or across multiplelocations.

Additionally, the various embodiments set forth herein are described interms of exemplary block diagrams, flow charts and other illustrations.As will become apparent to one of ordinary skill in the art afterreading this document, the illustrated embodiments and their variousalternatives can be implemented without confinement to the illustratedexamples. For example, block diagrams and their accompanying descriptionshould not be construed as mandating a particular architecture orconfiguration

What is claimed is:
 1. A method, comprising: receiving an input signalat a quantized phase shifter of a phased array antenna; obtaining a timeaveraged, phased shifted signal that reduces a quantization error of thephase shifter, wherein obtaining the time averaged phase shifted signalcomprises switching between two phase states of the quantized phaseshifter a plurality of times to obtain a time-averaged value of a stateof the quantized phase shifter that is between values of the two phasestates; and outputting the time averaged, phase shifted signal to anantenna element circuit of the phased array antenna.
 2. The method ofclaim 1, wherein switching between the two phase states of the quantizedphase shifter comprises switching between the two phase states of thequantized phase shifter at a rate greater than the highest symbol rateof an adjacent satellite.
 3. The method of claim 2, wherein switchingbetween the two phase states of the quantized phase shifter comprisesswitching between the two phase states of the quantized phase shifter ata rate at least four times greater than the highest symbol rate of anadjacent satellite.
 4. The method of claim 1, wherein the time averaged,phase shifted signal is obtained using at least linear interpolation oraccumulator interpolation.
 5. The method of claim 1, wherein obtainingthe time averaged, phase shifted signal comprises: obtaining an errorsignal by comparing an output phase to a required phase; and providingthe error signal as an input to an integrator to obtain an integratedsignal.
 6. The method of claim 5, wherein obtaining the time averaged,phase shifted signal comprises: unwrapping the output phase of theintegrated signal to obtain an unwrapped signal; and quantizing theunwrapped signal.
 7. The method of claim 1, wherein the quantized phaseshifter is 1-bit or 2-bit phase shifter.
 8. The method of claim 1,wherein the quantized phase shifter provides a constant phase shift ofan input signal over a frequency.
 9. The method of claim 1, wherein thequantized phase shifter provides a true time delay of an input signal.10. The method of claim 1, wherein switching between the two phasestates of the quantized phase shifter a plurality of times to obtain atime-averaged value of a state of the quantized phase shifter that isbetween values of the two phase states, comprises: using pulse widthmodulation duty cycles corresponding to the two phase states to obtainthe time-averaged value.
 11. A phased array antenna, comprising: aplurality of quantized phase shifters; a controller to switch betweenthe phase states of each of the plurality of quantized phase shifters toobtain a time-averaged, phase shifted signal from each of the pluralityof quantized phase shifters, wherein the controller is configured toobtain the time-averaged, phase shifted signal for each of the pluralityof quantized phase shifters by switching between two phase states of thequantized phase shifter a plurality of times to obtain a time-averagedvalue of a state of the quantized phase shifter that is between valuesof the two phase states; and a plurality of antenna elements, whereineach of the plurality of antenna elements is to receive thetime-averaged, phase shifted signal from a respective one of theplurality of quantized phase shifters.
 12. The phased array antenna ofclaim 11, wherein each of the plurality of quantized phase shifters is1-bit or 2-bit phase shifter.
 13. The phased array antenna of claim 11,wherein each of the plurality of quantized phase shifters provides aconstant phase shift of an input signal over a frequency.
 14. The phasedarray antenna of claim 11, wherein each of the plurality of quantizedphase shifters provides a true time delay of an input signal.
 15. Thephased array antenna of claim 11, wherein the phased array antenna is aphased array antenna of a very small aperture terminal (VSAT).
 16. Thephased array antenna of claim 11, wherein the phased array antenna is aphased array antenna of a satellite.
 17. The phased array antenna ofclaim 11, wherein the controller is to obtain the time-averaged, phaseshifted signal of each of the plurality of quantized phase shiftersusing at least linear interpolation or accumulator interpolation.
 18. Amethod, comprising: receiving an RF communication signal at each of aplurality of antenna elements of a phased array antenna; outputting asignal from an antenna element to a quantized phase shifter; andobtaining a time averaged, phased shifted signal that reduces aquantization error of the phase shifter, wherein obtaining the timeaveraged phase shifted signal comprises switching between two phasestates of the quantized phase shifter a plurality of times to obtain atime-averaged value of a state of the quantized phase shifter that isbetween values of the two phase states.
 19. The method of claim 18,wherein obtaining the time averaged, phased shifted signal comprises:obtaining an error signal by comparing an output phase to a requiredphase; and providing the error signal as an input to an integrator toobtain an integrated signal.
 20. The method of claim 18, wherein thetime averaged, phase shifted signal is obtained using linearinterpolation or accumulator interpolation.
 21. The method of claim 18,further comprising: amplifying the RF communication signal received ateach of the plurality of antenna elements using a low noise amplifier.